In key systems as generally known, line appearances at stations are hard wired and can only be changed by disconnection of the wires, as necessary. In addition, special features are also connected permanently as necessary and changed only by laborious disconnection and replacement as has been common in the telephone industry since the inception of cross connect distribution wiring.
In the case of key systems of the type shown in U.S. Pat. No. 3,935,396 issued Jan. 27, 1976, many lines can be provided with access to stations by time division signaling methods thereby minimizing the number of conductors extending from stations to lines. In such systems, the connection of speech conductors from lines to stations through crosspoint matrices are under memory control. Larger combinations of station and line access are feasible with systems of this type. However, the requirement of inflexible permanent wiring connections inhibit the possibility of changing line to station allocations and for changing special features being provided to one or more stations.